Here's some bad news for us Mombies (mums who stay up late even though they're exhausted, because it's kid-free time): being tired could make you eat more the following day.
An analysis of 11 previous studies, consisting of a total of 172 participants, found that after a night of limited sleep (around four hours) on average, people ate 358 more calories than those who slept for 7 – 12 hours. This, the researchers note, is the equivalent of about four and a half slices of bread.
And they weren't chowing down on fruit – sleep deprived participants consumed more fat and less protein. There was no impact, however, on carbohydrate consumption.
The authors of the paper, published last week in European Journal of Clinical Nutrition, conclude: "In the long term, this may implicate weight gain."
Senior author, Dr Gerda Pot, from the Diabetes & Nutritional Sciences Division at King's College London said in a statement: "The main cause of obesity is an imbalance between calorie intake and expenditure and this study adds to accumulating evidence that sleep deprivation could contribute to this imbalance. So there may be some truth in the saying 'early to bed, early to rise, makes a man healthy and wise'."
So why do we reach for the chocolate after a night spent scrolling Facebook or binge-watching Stranger Things? The authors cite a small study of 26 adults, which found that a night of limited sleep resulted in increased activation in areas of the brain linked to reward. As such, the researchers suggest that sleep deprivation may heighten the desire to seek food as a reward.
3pm trip to the vending machine, anyone?
In addition, clocking fewer hours of sleep, the authors explain, may also disrupt the internal body clock affecting the body's regulation of the hormones that control appetite.
While acknowledging the short-term and lab-based nature of the studies and the need for more research, study co-author Haya Al Khatib noted: "Our results highlight sleep as a potential third factor, in addition to diet and exercise, to target weight gain more effectively."
All the more reason to have an early night …